A synthetic test circuit, comprising: a device under test including a chain-link converter under test, comprising a plurality of test modules, each test module including module switches connected with an energy storage device; a terminal connected to the device under test; at least one injection circuit operably connected to the terminal, the injection circuit including a source, the source including a source chain-link converter, which includes a plurality of source modules, each source module including a plurality of module switches connected with at least one energy storage device; a controller being configured to operate each source module to selectively bypass the corresponding energy storage device and insert the corresponding energy storage device into the corresponding source chain-link converter so as to generate a voltage across the source chain-link converter and thereby operate the injection circuit to inject a current waveform and/or a voltage waveform into the chain-link converter under test.

A synthetic test circuit, for performing an electrical test on a device under test, is provided. The circuit includes a terminal connectable to the device under test; a voltage injection circuit-operably connected to the terminal, the voltage injection circuit including a voltage source, the voltage source including a chain-link converter, the chain-link converter including a plurality of modules, each module including a plurality of module switches connected with at least one energy storage device; and a controller-configured to operate each module of the voltage injection circuit to selectively bypass the or each corresponding energy storage device and insert the or each corresponding energy storage device into the chain-link converter so as to generate a voltage across the chain-link converter and thereby operate the voltage injection circuit to inject a unidirectional voltage waveform into the device under test.

Provided is an assistance apparatus for localizing errors in a monitored technical system consisting of devices and/or transmission lines, including at least one processor configured to obtain values of actual attributes of the devices and/or of the transmission lines, determine an error probability for each device and/or transmission line by processing a graph neural network with the obtained actual values of attributes as input, wherein the graph neural network is trained by training attributes assigned to an attributed graph representation of the technical system, and output an indication for such devices and/or transmission lines, whose error probability is higher than a predefined threshold.

A test apparatus for testing at least one switch device for a high-voltage battery of a vehicle, includes a voltage source for generating an electrical test voltage between a positive high-voltage path and a negative high-voltage path of the at least one switch device. The test apparatus has a first connecting device and a first current source for feeding a first electrical test current into the positive high-voltage path, wherein the first connecting device, the first current source and the positive high-voltage path together form a first circuit when testing the at least one switch device. The test apparatus has a second connecting device and a second current source for feeding a second electrical test current into the negative high-voltage path, wherein the second connecting device, the second current source and the negative high-voltage path together form a second circuit when testing the at least one switch device.

A protective relay test equipment operation device according to an embodiment of the present invention may comprise: a switch unit for, upon reception of a trip signal or a close signal from a protective relay, changing an electrical connection state between a first port configured to be electrically connected to test equipment that generates a test signal and a second port configured to be electrically connected to the protective relay; a measurement unit for measuring a voltage and a current between the first port and the second port during a test period in which an operation time point of the switch unit is a start time point or an end time point; and a calculation unit for calculating a plurality of time point-specific impedance values within the test period according to a measurement result of the measurement unit.

A method for testing capacitive current switching of a circuit breaker, including: realizing a capacitive current switching by the circuit breaker, measuring voltage at the terminals of the circuit breaker after the capacitive current switching, calculating the gradient of the measured voltage, determining whether there is at least one point of gradient whose amplitude exhibits an absolute value greater than a first predetermined threshold, and when such a point is determined, identifying the instant of appearance of the determined point and of the amplitude of variation of the voltage at that instant, as voltage drop.

A thyristor valve test system based on cooperation of logic functions of software, wherein the test system comprises: a thyristor valve (5) to be tested, a VBE (3) and a tester (4), and the VBE (3) has a dedicated test mode, the tester (4) provides three steps for each test item. The thyristor valve (5) to be tested and the VBE (3) are connected by optical fibers (1), and the thyristor valve (5) to be tested and the tester (4) are connected by cables (2), and there is no connection between the VBE (3) and the tester (4).

A test apparatus for testing at least one switch device for a high-voltage battery of a vehicle, includes a voltage source for generating an electrical test voltage between a positive high-voltage path and a negative high-voltage path of the at least one switch device. The test apparatus has a first connecting device and a first current source for feeding a first electrical test current into the positive high-voltage path, wherein the first connecting device, the first current source and the positive high-voltage path together form a first circuit when testing the at least one switch device. The test apparatus has a second connecting device and a second current source for feeding a second electrical test current into the negative high-voltage path, wherein the second connecting device, the second current source and the negative high-voltage path together form a second circuit when testing the at least one switch device.

Test system and method comprise a controller, which can be microprocessor derived and include operating system for programmability, to control low voltage signals and feedback for managing the test system. High potential test system can include an amplifier comprising solid-state and/or passive components amplifying lower voltage signal to produce higher voltage output signal based on signal monitoring and control provided by controller. Controlled higher voltage output signal can be injected into high voltage multiplier circuit resulting in high DC voltage output voltage up to 50 kV or higher range. The monitoring can include feedback indicative of higher voltage signal output of amplifier and/or high DC voltage output voltage of high voltage multiplier circuit. System feedback and control can be fully automated, or selectively user-controlled via a user interface providing continuous and/or selective monitoring and display of system parameters and measured signal inputs and/or outputs.

A protective relay test equipment operation device according to an embodiment of the present invention may comprise: a switch unit for, upon reception of a trip signal or a close signal from a protective relay, changing an electrical connection state between a first port configured to be electrically connected to test equipment that generates a test signal and a second port configured to be electrically connected to the protective relay; a measurement unit for measuring a voltage and a current between the first port and the second port during a test period in which an operation time point of the switch unit is a start time point or an end time point; and a calculation unit for calculating a plurality of time point-specific impedance values within the test period according to a measurement result of the measurement unit.